  *{
    margin: 0;
    padding: 0;
   }
    html,body,#app{
      width: 100%;
      height: 100%;
    }
  
    ul,ol{
      list-style: none;
    }
    a{
      text-decoration: none;
    }
    img{
      display: block;
    }

    .main{
        min-width: 320px;
        max-width: 750px;
        margin: 0 auto;
    }